Refers to the skin or outer layer of something, often used in culinary contexts.
La casquera de la naranja es rica en fibra y puede ser utilizada para hacer mermelada.
The peel of the orange is rich in fiber and can be used to make marmalade.
La casquera de la fruta que compré era gruesa y difícil de pelar.
The peel of the fruit I bought was thick and hard to remove.